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After that, I got her to swim underwater. Now she can breaststroke the length of the pool, kicking and breathing rhythmically, and only occasionally reverting to the chicken thrash.
随后，我让她下水练习游泳。现在，她能够采用蛙泳游完整个泳池，并且有节奏地踢腿和控制呼吸，偶尔才会在水里胡乱扑腾。
I have now pronounced her pool-safe. The amount of water she has ingested has decreased markedly over the last two weeks.
我对她说泳池很安全。在过去的两周里，她喝的水已经明显变少了。
But it’s the swallowing that gets a swimmer to thinking: What’s in this stuff?
但正是不断从泳池中喝水的过程让游泳者开始思考：游泳池的水里都有什么?
Swimming pool water has a distinctive odor, a chemical byproduct of chlorine interacting with body oils, sweat and urine. Yes, urine. Some bad-mannered people actually pee in pools around the world.
游泳池的水有一种独特的气味，它是由氯与人的油脂、汗水和尿液混合在一起所产生的化学物质的浓烈味道。是的，这里面有尿液。实际上，世界各地的游泳池里都有低素质的人在里面撒尿。
The amount of pee has been difficult to measure until now. Xing-Fang Li of the University of Alberta explained in February how her team did it. Instead of trying to measure pee directly, they measured the level of an artificial sweetener — acesulfame potassium, or Ace-K — which is carried in most people’s urine, including in China. It’s found in many foods, such as yogurt. It’s not metabolized. In other words, it goes right through you, thereby providing a urine yardstick.
目前为止，尿液具体含量一直难以测量。今年2月，加拿大阿尔伯塔大学的李兴芳教授向外界解释了她的团队如何测量泳池中的尿量。研究团队没有直接测量尿液，而是测量了一种名叫乙酰磺胺酸钾（或者简短地称为Ace-K）的人造甜味剂含量。这种甜味剂在大多数人的尿液中存在，其中也包括中国人。它来源于许多食物，比如酸奶，但是它在人体内不代谢。换句话说，它通过人体然后排入泳池，从而提供了一个尿液衡量标准。
Li’s team collected water samples from public pools, hotel hot tubs and recreation venues and tested for Ace-K. Result: An 833-cubic-meter pool contains about 0.08 cubic meters of pee.
李兴芳的团队从公共泳池、酒店热水浴缸和娱乐场所收集了液体样本，并对其中的Ace-K含量进行了检测。结果显示，一个833立方厘米的水池含有大约0.08立方米的尿液。
